# code15.py

import threading

class FirstProcess(threading.Thread):

def __init__(self, lock_a, lock_b):

self.lock_a = lock_a

self.lock_b = lock_b

def run(self):

with self.lock_a:

# Acquire the first lock

with self.lock_b:

# Acquire the second lock for another concurrent task

class SecondProcess(threading.Thread):

def __init__(self, lock_a, lock_b):

self.lock_a = lock_a

self.lock_b = lock_b

def run(self):

with self.lock_b:

# Acquire the first lock

# Notice that this thread require the lock_b, that

# could be taken fot other thread previously

with self.lock_a:

# Acquire the second lock for another concurrent task

lock_a = threading.Lock()

lock_b = threading.Lock()

t1 = FirstProcess(lock_a, lock_b)

t2 = SecondProcess(lock_a, lock_b)

t1.start()

t2.start()